Forming tool for leading edge of turbine blades

ABSTRACT

A forming tool for forming leading edges of turbine blades is disclosed. In various embodiments, a forming tool may comprise a cylindrically-shaped body having a notch around the circumference of the cylindrically-shaped body. The notch may be positioned perpendicularly to a center axis of the cylindrically-shaped body. Further, the notch may have a notch contour with an upper notch contour and a lower notch contour, and where the notch contour is a relief of a selected turbine blade leading edge. The forming tool may be a grinding tool or a cutting tool. Moreover, a forming process may comprise forming, by a forming tool, a first portion of a turbine blade leading edge with a rough edge result, and forming, by a milling cutter, a second portion of the turbine blade leading edge with a rough edge result.

FIELD

The present disclosure relates to forming leading edges of turbineblades, and more particularly, to a forming tool with designed reliefnotches for forming the leading edges of fan blades and compressorblades.

BACKGROUND

In the machining of rotor blades, for example rotor blades used in anintegrally bladed fan and/or compressor, point milling is usuallyemployed for cutting the leading edge. If the rotor blades are thin, itis difficult to machine the very tip of the leading edge due tochattering and deflection induced by the cutting action. The resultingtip of the leading edge may deviate from an ideal shape, which mayresult in impaired aerodynamic performance. A typical prior art processof forming a fan or compressor blade edge includes removing materialfrom a blade edge, leaving the blade with a rough edge. Additional bladeedge material is then removed to form a semi-finished edge.Point-milling may be applied to the semi-finished blade edge to form afinished edge.

SUMMARY

A forming tool for forming leading edges of turbine blades is disclosed.In various embodiments, a forming tool may comprise acylindrically-shaped body having a notch around the circumference of thecylindrically-shaped body. The notch may be positioned perpendicularlyto a center axis of the cylindrically-shaped body. Further, the notchmay have a notch contour with an upper notch contour and a lower notchcontour, and the notch contour may be a relief of a selected turbineblade leading edge. The forming tool may be a grinding tool or a cuttingtool.

Moreover, in various embodiments, a forming process may compriseforming, by a forming tool, a first portion of a turbine blade leadingedge with a rough edge result, and forming, by a milling cutter, asecond portion of the turbine blade leading edge with a rough edgeresult. The first portion may be the edge tip area of the turbine bladeand the second portion may be the remaining area of the turbine blade.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements.

FIG. 1 illustrates, in accordance with various embodiments, aperspective view of a forming tool in contact with a turbine blade;

FIG. 2 illustrates, in accordance with various embodiments, a sectionalview of a forming tool;

FIG. 3 illustrates, in accordance with various embodiments, a sectionalview of a forming tool with cutting edges and flutes;

FIG. 4 illustrates, in accordance with various embodiments, multiplevariations of notch contours of a forming tool;

FIG. 5 illustrates, in accordance with various embodiments, an exemplaryforming process of a turbine blade leading edge;

FIGS. 6A-6B illustrate various stages of a forming process of a turbineblade using a point milling tool;

FIG. 6C illustrates an exemplary forming process of a turbine bladeusing an exemplary forming tool; and

FIG. 7 illustrates, in accordance with various embodiments, aperspective view of a forming tool with multiple notches.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration and their best mode. While these exemplary embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the inventions, it should be understood that other embodimentsmay be realized and that logical, electrical, and mechanical changes maybe made without departing from the spirit and scope of the inventions.Thus, the detailed description herein is presented for purposes ofillustration only and not of limitation. For example, the steps recitedin any of the method or process descriptions may be executed in anyorder and are not necessarily limited to the order presented.Furthermore, any reference to singular includes plural embodiments, andany reference to more than one component or step may include a singularembodiment or step. Also, any reference to attached, fixed, connected orthe like may include permanent, removable, temporary, partial, fulland/or any other possible attachment option. Additionally, any referenceto without contact (or similar phrases) may also include reduced contactor minimal contact.

A forming tool for shaping a leading edge of a turbine blade isdisclosed. In accordance with various embodiments, and with reference toFIG. 1, a forming tool 100 is a rotary tool and may comprise acylindrically-shaped body 101 having a notch 102 spanning acircumference of the cylindrically-shaped body 101. As shown, theforming tool 100 is in contact with a leading edge 151 of a turbineblade 150 near an edge tip 152. In various embodiments, the forming tool100 may be in contact with the edge tip 152 and substantially centeredon the nose point. As used herein, the edge tip 152 is the distal end ofthe blade away from a rotor attachment point. Further, as used herein,the nose tip is the geometric center of the leading edge. Thecylindrically-shaped body 101 may comprise a carbide material, typicallyin the form of a cylinder, though other shapes may be implemented. Thecarbide material may include calcium carbide, silicon carbide, ironcarbide, or tungsten carbide. The body 101 may also be at leastpartially comprised of diamond material or other cutting materials. Invarious embodiments, the surface of the notch 102 may be formed of acutting material, for example, a cemented tungsten carbide wrappedaround a carbide blank. In various embodiments, the cylindrically-shapedbody 101 may be about ⅜ inch in diameter. Moreover, in variousembodiments, the forming tool 100 may further comprise at least one of adiamond coating, a nitride coating, or a titanium nitride (TiN) coatingon a surface of the notch 102. In various embodiments, a diamondmaterial may be embedded to the surface of the notch 102. The coating orinsert may increase the hardness of the forming surface and increase theusable life of the forming tool.

In various embodiments, and with reference to FIG. 2, the notch 102 maybe positioned perpendicularly to a center axis 201 of thecylindrically-shaped body 101. Furthermore, the notch 102 may have anotch contour with an upper notch contour 202 and a lower notch contour203, and wherein the notch contour is a relief of a selected turbineblade leading edge. The notch 102 may comprise a recess about thecircumference of the body 101 of the forming tool 100.

In various embodiments, the forming tool 100 may be a grinding formingtool used to grind a blade edge. In various embodiments and withreference to FIG. 3, a forming tool may be a cutting forming tool 300used to cut a blade edge. The cutting forming tool 300 may comprise acylindrically-shaped body 301 having a notch 302 spanning acircumference of the cylindrically-shaped body 301, at least four flutes303 about the notch 302 and at least four cutting edges 304. Forexample, four cutting edges 304 may be spaced equidistant around thecircumference of the cylindrically-shaped body 301, thereby creatingfour flutes 303. The flutes are the grooves that allow for the cutmaterial to be ejected as the cutting occurs.

As mentioned above with reference to FIG. 2, the notch 102 may have anupper notch contour 202 and a lower notch contour 203. Each of the upperand lower notch contours may have independently designed contours. Theupper notch contour 202 and lower notch contour 203 may have the samecontours or may have different contours. As used herein, “same contour”may refer to a notch contour having the same notch radii, same notchdepth, and same notch height as another notch contour. Further, as usedherein “different contour” may refer to different notch radii, differentnotch depth, different notch height, or combinations of thereof withregard to at least two notches. A designed notch contour may havedifferent portions and shapes, some of which are shown in FIG. 4. Thedesigned notch contour may typically be an elliptical shape. Forexample, contour variation 400A illustrates a single radii curvature (R)connected a line segment (L). Variation 400B illustrates a first radiicurvature (R₁) connected to a second radii curvature (R₂), and thesecond radii curvature (R₂) is connected to a line segment (L). Thedesigned contour variation 400C illustrates a first radii curvature (R₁)connected to a first line segment (L₁), the first line segment (L_(i))connected to a second radii curvature (R₂), and the second radiicurvature (R₂) is connected to a second line segment (L₂). One exampleof a designed notch contour may include first portion having a firstradii curvature of 0.005 inches connected to a second portion have asecond radii curvature of 0.022 inches. Further, as would be understood,the designed contour may comprise any number of radii curvatures and anynumber of line segments. Further, the designed contour may comprise apoint-defined contour, as illustrated in contour variation 400D.

The notch contour of the notch may be designed to be a relief of aselected turbine blade leading edge. In various embodiments, the leadingedge of the edge tip area of a turbine blade may be approximately1/30,000 inch thick, and the tolerance of the finished edge may beapproximately ± 1/2000 of an inch. The designed contour and theadditional support provided by the forming tool may facilitate achievingthis tolerance level. The forming tool is more precise than handscraping, and tends to reduce processing times.

In accordance with various embodiments, and with reference to FIG. 5, aforming process 500 may comprise forming, by a forming tool, a firstportion of a turbine blade leading edge with a rough edge result 501,and forming, by a milling cutter, a second portion of the turbine bladeleading edge with a rough edge result 502. In various embodiments, arough edge result may be the partially finished condition of a leadingedge that has had some of the leading edge material removed but is notyet at a final shape. The first portion may be an edge tip area of theturbine blade and the second portion may be the remaining area of theturbine blade. The forming tool used in the forming process may be thesame as or similar to forming tool 100 or forming tool 300 as disclosedherein. For illustrative purposes, FIGS. 6A-6C show a process of aforming tool shaping a leading edge of a turbine blade. FIG. 6Aillustrates an exemplary turbine blade 601 having an unshaped leadingedge 602. FIG. 6B illustrates an exemplary turbine blade 601 with aleading edge 602 that has been shaped by a point milling tool. FIG. 6Cillustrates a close-up of a forming tool 610 removing material from theleading edge 602 of the turbine blade 601, resulting in partiallyfinished leading edge, depending on the desired finished shape.

In an exemplary process, edge material is not cleared from the bladeedge, which reduces the process by a step and decreases the processingtime. Furthermore, the edge forming process may occur later in the bladeforming process compared to prior art processes, for example after theturbine blades are not connected to a support frame. Moreover, theforming process may be applied to turbine blades that are independentfrom other blades or other support structures. In prior art processes, aturbine blade is typically still attached to adjacent blades or othersupport structures when the edges are forming. The additional attachmentprovides support to reduce vibrations caused by a cutting tool formingthe blades. In the exemplary process, the notch is in contact with thetop and bottom of the blade's leading edge, and provides the support tothe edge tip area of the blade to reduce vibration during the formingprocess.

The leading edge of a turbine blade near the edge tip area may thethinnest, and then broadens as the blade edge approaches the rotor.Accordingly, the desired leading edge shape may also increase in sizelong the edge. In accordance with various embodiments and with referenceto FIG. 7, a forming tool 700 may comprise a cylindrically-shaped body701 having a first notch 702 and a second notch 703, each notch 702, 703individually located around the circumference of thecylindrically-shaped body 701. First notch 702 and second notch 703 areeach similar to notch 102 described above. In various embodiments, afirst notch contour of the first notch 702 may be different than asecond notch contour of the second notch 703. The different contourshapes may be designed to accommodate for the different edge shapesalong a blade's leading edge. An exemplary forming process may includeimplementing a single forming tool and then applying multiple notchcontours of the single forming tool at the selected portions of theturbine blade. In other various embodiments, the first notch contour ofthe first notch 702 may be the same as the second notch contour of thesecond notch 703. Each notch contour being the same may be beneficialfor increasing the usable life of the forming tool 700. The first notch702 and second notch 703 may be swapped for use during the formingprocess. This allows the notch area to cool between uses and extendusable life.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the inventions. The scope of the inventions is accordinglyto be limited by nothing other than the appended claims, in whichreference to an element in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.”Moreover, where a phrase similar to “at least one of A, B, or C” is usedin the claims, it is intended that the phrase be interpreted to meanthat A alone may be present in an embodiment, B alone may be present inan embodiment, C alone may be present in an embodiment, or that anycombination of the elements A, B and C may be present in a singleembodiment; for example, A and B, A and C, B and C, or A and B and C.Different cross-hatching is used throughout the figures to denotedifferent parts but not necessarily to denote the same or differentmaterials.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment”, “an embodiment”,“various embodiments”, etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment.

Further, when a particular feature, structure, or characteristic isdescribed in connection with an embodiment, it is submitted that it iswithin the knowledge of one skilled in the art to affect such feature,structure, or characteristic in connection with other embodimentswhether or not explicitly described. After reading the description, itwill be apparent to one skilled in the relevant art(s) how to implementthe disclosure in alternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element herein is to be construed under theprovisions of 35 U.S.C. 112, sixth paragraph, unless the element isexpressly recited using the phrase “means for.” As used herein, theterms “comprises,” “comprising,” or any other variation thereof, areintended to cover a non-exclusive inclusion, such that a process,method, article, or apparatus that comprises a list of elements does notinclude only those elements but may include other elements not expresslylisted or inherent to such process, method, article, or apparatus.

1. A forming tool comprising: a cylindrically-shaped body having a notchspanning a circumference of the cylindrically-shaped body, wherein thenotch is positioned perpendicular to a center axis of thecylindrically-shaped body, wherein the notch has a notch contour with anupper notch contour and a lower notch contour, and wherein the notchcontour is a relief of a selected turbine blade leading edge.
 2. Theforming tool of claim 1, wherein the forming tool is a cutting formingtool.
 3. The forming tool of claim 2, wherein the cutting forming toolcomprises at least four flutes at an interior point of the notch.
 4. Theforming tool of claim 1, wherein the forming tool is a grinding formingtool.
 5. The forming tool of claim 1, wherein the forming tool is madeof a carbide material.
 6. The forming tool of claim 1, wherein theforming tool is made of diamond.
 7. The forming tool of claim 1, furthercomprising at least one of a diamond coating, a nitride coating, and aTiN coating on a surface of the notch.
 8. The forming tool of claim 1,wherein the upper notch contour is the same as the lower notch contour.9. The forming tool of claim 1, wherein the upper notch contour isdifferent from the lower notch contour.
 10. The forming tool of claim 1,further comprising a second notch around the circumference of thecylindrically-shaped body, wherein the second notch is positionedperpendicularly to the center axis of the cylindrically-shaped body, andwherein the second notch has a second notch contour.
 11. The formingtool of claim 10, wherein the second notch contour is different from thenotch contour.
 12. The forming tool of claim 10, wherein the secondnotch contour is the same as the notch contour.
 13. A forming processcomprising: forming, by a forming tool, a first portion of a turbineblade leading edge in rough condition; forming, by a milling cutter, asecond portion of the turbine blade leading edge in rough condition;wherein the forming tool has a notch around the circumference of acylindrically-shaped body, and wherein a notch contour of the notch is arelief of a selected turbine blade leading edge
 14. The method of claim13, wherein the first portion of turbine blade leading edge is an edgetip area.
 15. The method of claim 13, wherein the turbine blade isindependent from at least one of a second turbine blade and a supportstructure during the forming process.
 16. The method of claim 13,further comprising providing, by the forming tool, support to an edgetip area of the blade to reduce vibration during the forming process.17. The method of claim 16, wherein the forming tool makes contact onleast two surfaces of the blade edge during the forming process.